Projected beam smoke detector systems utilize a transmitter to send a beam of radiant energy across a region to a prelocated receiver. The receiver can in turn be coupled to an alarm system or alarm panel.
Under normal ambient conditions, a known signal level is generated within the receiver in response to the incident beam. In the event that smoke begins to fill the region between the transmitter and receiver, airborne particles therefrom will interfere with the transmission of the beam to the receiver.
When the particle density is great enough in the atmosphere, the signal generated internally in the receiver due to the incident beam, will drop. When the signal drops below a predetermine threshold, the receiver generates an alarm signal to the alarm system or panel.
Projected beam systems have been found to be very useful where coverage is to be provided over a region. However, the transmitter/receiver pairs of the prior art systems have been expensive to install because it has been difficult to carry out the required alignment process.
One known approach that has been used in connection with aligning transmitter/receiver pairs has been to connect a volt meter to a receiver and to adjust the receiver and/or the transmitter to maximize the measured output voltage from the sensor and the receiver. This has been a relatively slow process and as a result such installations have been expensive. In addition, access to the electrical signals must be provided for coupling the voltmeter thereto.
Hence, there continues to be a need for a way to install and align transmitter/receiver pairs for use in projected beam smoke detector systems more efficiently and cost effectively than heretofore has been possible. Preferably, the alignment apparatus will be self-contained, not require the use of external instruments and will not add an appreciable cost to such a system.